Childhood bronchial asthma:Effects of passive smoking and breastfeeding on age at onset and severity

Abstract

Bronchial asthma is a disease characterized by hyper-reactivity of respiratory airways to gaseous and particulate matter in the air. cigarette smoke is an important source of indoor air pollution and an increased rate of bronchitis and pneumonia in children of smokers is well documented. The association between bronchial asthma and passive smoking is not well defined. Although breast milk is known to protect against respiratory infections, the association between breast-feeding and asthma is not well described. It was with these unanswered questions in mind that this study was carried out. objectives The obj ecti ves of the study were to determine the effects of

passi ve smoking and breast-feeding upon the age of onset and severity of bronchial asthma in children. Materials and methods A case control study was carried out at Kenyatta National Hospital, Nairobi, between December 31st 1992 and April 27th 1993 on 450 children aged between 1 and 120 months. Children with bronchial asthma were matched by age to two different groups of controls in t a 1:1 ratio. Cases and controls were subjected to a standardized questionnaire to gather information on age at onset of wheezing, frequency of asthmatic attacks; duration of breast-feeding and history of cigarette smoking in the family. Results There was a significant association between passive smoking and onset of bronchial asthma in the first year of life, OR=3.5 (95% C.I. ~.4, 8.7), P=O.004. There also appeared to be a significant association between passive smoking and asthma

severity. No association was found between breast-feeding and age at onset of asthma, but exclusive breast-feeding significantly reduced chances of developing severe forms of bronchial asthma, O.R.=0.37 (95% C.I. 0.14, 0.98, x2=4.62, p=0.05. Conclusions and recommendations Passive smoking predisposes not only to early onset of bronchial / asthma, but possibly also to more severe forms of the disease. This study has found that breast-feeding appears to be protective against severe forms of asthma. It is strongly recommended that young children should not be exposed to cigarette smoke. A prospective study is recommended for further evaluation of the association between breast-feeding and severity of bronchial asthma in childhood .